Cyanoacrylate adhesives: The history that abounds relative development of CA is this. It was developed as an alternative to sutures and bandages for treating open battlefield wounds during the Vietnam War. This seems to make sense in light of its ability to instantly weld the fingers together of any careless modeler. That little bottle of instant repairs that you buy is actually a chemical called cyanoacrylate monomer which, except for an inhibitor, would instantly form a single plastic blob of polymer with accompanying heat and fury that would resemble the China Syndrome. CA was on the market for a number of years before it came to the construction hobbies. The adhesive was so fluid that it could only be used to mend nonporous materials like ceramic, plastic, and glass. It certainly did not work on balsa, which merely soaked it up like a sponge. Later, when viscosity modifiers were added, it became generally useful and ended up "in our hands" (pun intended). The advantages of CA are speed and hold. The disadvantages are cost, vapor, and brittleness. Please be your own judge but I will not use it for whole plane construction. It has a place and is excellent in certain applications. For many butt joints and T-joints, CA is too brittle, especially in large airplanes. Aliphatic glue is a much better choice. CA is specified as the adhesive of choice for wing skins. In this application, it is too hard and makes sanding to an invisible butt joint very difficult. Animal glue like Sigment is the quintessential choice since it is the sole truly sandable adhesive. Cyanoacrylates are excellent for tacking parts into place to speed up construction followed by regluing with an aliphatic adhesive. CA is unequalled for making repairs and piecing a crashed beauty back together. When you use CA, be careful not to draw debris such as sawdust or baking soda (incidentally a good inexpensive accelerant) into the bottle. It may cause the entire contents to harden.

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Aliphatic glue: The parent for this type of glue is doubtlessly Borden's white glue. Borden's is a very strong glue which penetrates wood well. A second generation of such glues contains fillers which render them somewhat "sandable." Regardless of the claims, none are truly sandable since their binder is rubbery. In my mind, more expensive is not better. The hobby store brands like Pica's "Gluit" and others are expensive and not very sandable. Borden's yellow woodworkers glue is strong, inexpensive, and as sandable as any I have found. On large built up fuses and wings, I recommend using Borden's woodworkers glue for most of the "inside" construction including attachment of the skin. But I glue the skins together and other places to be subsequently sanded with Sigment. Firewalls, landing gear blocks, and hard points are attached with epoxy.

Silicon caulk or RTV: This is an excellent adhesive which does not harden. This provides considerable shock absorption. This material is particularly good for attaching parts inside fiberglass fuselages. There must be ample gluing surface. Fiberglass flexes in a finished airplane during flight will cause brittle joints made with CA epoxy or other adhesives to fail. Many servo trays have broken loose during a hard landing. Certainly, you have noticed the vinegar-like smell of silicon adhesive when it cures. Do not use this adhesive around electrical components. Connect cells in a battery with hot melt adhesive. Rubber cement: The next time you want to make little protective foam boxes for your receivers or batteries use rubber cement. It maintains its flexibility and will never let go once it is dry.

3M Spray Adhesive: Formula 77 is excellent for attaching paper rib and bulkhead patterns to balsa or plywood during scratch building. If you want to remove the pattern from the wood after cutting, allow the adhesive to dry on the paper for more than a minute before applying. The paper will not stick quite so tightly and the adhesive will not transfer to the wood. 3M can also be used to hold 6oz. fiberglass in position on the wing center while epoxy or polyester resin is applied. It is great to hold plans flat on building board.

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BUYING USED EQUIPMENT - by Bryan Jones [from The Flightline, Pearland TX, Bryan Jones, editor.]

Have you ever been presented with a deal too good to be true? Sometimes they are good deals, other times... well. One thing we have in our benefit living in the Houston area is a very large group of RC airplane flyers. There are several outlets for buying and trading model airplanes and their related accessories. Regardless of where you go to find the used equipment you desire, there are a few tips I have learned you may want to consider.

Airframes- These are the easiest items to inspect. The first and easiest items to check is the covering or paint. Having a well-applied and thoroughly sealed covering or coating is important in keeping oil and other materials from the underlying wood or fiberglass. Water or oil soaked structures will eventually weaken and fail. Look in the engine compartment for the sealing I have mentioned. Exposed wood is easy to spot. Another area critical to an airplane's structural integrity is the wing saddle and attachment structure. Look here for cracks or evidence of previous repairs. Generally, any joint having been repaired will be weaker than originally constructed. If the joint shows sign of repair, this indicates design or crash damage. Assume it is crash damage and inspect the tail feathers and other exposed inner surfaces in the fuselage.

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Wings are a little more of a mystery than the fuselage. Without breaking the wing, place it over your knee and apply bending pressure. Listen for cracking noises (Stop then!). Look for splinters falling out any openings. Check control surface tightness and proper operation. Look for wing tip damage. Wing tip damage comes in two forms: first, the underside scrapes caused from ground loops and hard landings. Second the crunching effect on the end of the wing tip caused by cartwheels. Cartwheels will trash a model quicker than almost anything.

Engines- Purchasing a used engine is not quite as easy as purchasing an empty airframe. The first item of concern is external damage. Look for dirt, particularly that packed in between the forward cooling fins or around the carburetor. This is a pretty good indicator of a crash. Don't forget looking for the broken cooling fins and bent needle valves. Once you have checked the engine externally, look at the cylinder head. Assure all head bolts are present. Check the crankshaft. Look for buggered threads.

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One thing I strongly recommend is checking the shaft for run out with a dial indicator or similar instrument. I wouldn't accept any more than 0.002" TIR (total indicated run out) on .60 and smaller engines; 0.003" TIR on all others. Bear in mind, this measurement should be weighed in relation to the rest of the engine and these run out measurements are pretty high.

Look into the exhaust port on the cylinder. If the muffler is attached, remove it. Slowly turn over the engine while feeling the condition of the bearings and the piston/cylinder liner fit. Look down the port at the piston and the liner. Look for gouging and excessive scraping or scratches. Feel the engine as it is turned over. Notice any grinding or gritty feel in the bearings. Try and find out if the engine has ball bearings or sleeve bearings on the shaft. A ball bearing engine (with good bearings) is more valuable.

Hang onto that dial indicator we used earlier and set it up to check shaft looseness. When you get the indicator set up, pull the shaft in the opposite direction than it is being pulled when you set up the indicator. On engines 60 or smaller, 0.001" to 0.002" is reasonable. Larger engines can withstand 0.003" to 0.005" looseness. Finally, check the thrust on the shaft. While holding the engine in one hand, push and pull the shaft while turning it. Note any noises or unusual feels such as metal on metal rubbing or gritty feel. This is not particularly a problem in the inactive or reverse thrust direction, but may be a real problem indicator in the active or normal thrust direction.

I have purposely skipped the four-cycle engines for a couple of reasons. First, this subject deserved more space than available and second, I would have to research the issue more before writing.

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Radio Gear- This is a more challenging area than the previous two. Bear in mind the consequences of a complete radio failure... not pretty. Keep this in mind when you are about to make that killer deal. I have a few easy items to look for when buying used radio gear. These items typically do not indicate the actual condition of the internals but are a very representative indicator.

First, the general external appearance of the transmitter, receiver, and servos are important. Look for dirt, glue, or fuel residue. None are good. Even more important, check the switch harness from one end to another if you must use a used item. I don't recommend it. I only use switches I have purchased new. One failed switch or switch lead and the game is over.

The external condition of the transmitter is a good indicator of how the entire system was treated by its previous owner. Check the bottom and back of the transmitter case for excessive scratches. This indicates the amount of use the system has had. Less scratches, less use, good, good. Check the feel of the gimbals. Smooth and tight. Check the trim switches and auxiliary switches. Extend the antenna, checking for bends or damage. Turn on the transmitter and check the output/power needle response. Obviously the batteries may be dead or undercharged.

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Look at the receiver antenna. Is it in good shape? A kinked or stressed antenna indicates rough use and possible damage. Look for cracks in the case. Check for narrow band certification. Check for bent pins in the open sockets.

The servos are the least important items, but don't forget, it only takes one well-placed servo failure to wreck your plane. First, check the outward appearance. The leads are important as well. Look to see if the wires are damaged where they are attached to the plug. Look for plug damage. CAREFULLY check the gear train by rotating the servo head. If you strip the servo, you may have to buy a wrecked servo. Don't do this step if you don't feel sure of what you are doing. If you do, feel and listen for broken gear teeth.

Flight battery pack -- be very careful. I wouldn't recommend using a flight pack if you don't have a cycler/charger to verify the capacity and health of the battery. Don't forget to look at the lead. It's just as important as the battery switch.

Finally, connect the components of the system and operate with the transmitter. Check each channel individually, check dual rates, cheek programmability (if applicable), check servo response (noise, chatter, dragging, speed, etc.). If possible, perform a range check -- collapsed antenna at 200 feet minimum fully operational.

These are just a few items to keep in mind when purchasing used equipment. Even if everything checked out as described here, there is a possibility that the equipment was near breaking down or someone was trying to sell away a hidden problem.

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COLOR PERCEPTION - by Clay Ramskill [Adapted from an article by Dr. Robert Suding, published in MAA, Russ Roepke, editor, Temple Texas.]

How many times have you seen it? A plane crashes -- not from equipment failure or specific pilot dumb thumbs, but because the pilot couldn't tell what his plane was doing! Often as not, the plane involved was covered in a relatively dark, solid color.

We all know that we must see our aircraft to control them. We must not only see the plane, but know its attitude -- the relative positioning of the plane with respect to the earth. How we cover or paint the plane has a lot to do with our ability to do this, under the various conditions under which we fly.

The Color. The accompanying chart gives relative visibility for various colors, but doesn't note under which conditions it's good for. It should be pretty obvious that the background is important, too. For instance, white is listed as a top contender -- but we know that a white plane can really disappear against a light cloud background. A dark blue plane shows up fine in a clear sky -- but nearly disappears when you drop down in front of the tree line.

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The Pattern. Small, intricate patterns may look great, but will essentially disappear at any distance and are of little help as far as flying the plane is concerned. Larger patterns are better here -- but they should somewhat conform to the shape of the plane. Let's face it -- large irregular blobs are regularly used as CAMOUFLAGE for planes and ships. You see something (it's hard to completely hide a large airplane or ship!), but since it doesn't conform to the SHAPE you're looking for, you mind dismisses it!

Shades. The part of your eye that perceives illumination (in black and white) is 2000 times more sensitive than the part that perceives color. As your plane gets farther away, the actual colors get less prominent. But you can still easily see differences in brightness. So CONTRAST becomes very important. This is even more true under poor lighting conditions! At a distance or in poor lighting, the difference between green and blue just doesn't show up, but you WILL see the contrast between a light color and a dark color. Note that as we age, our color perception gets even worse. Bad news for those of us in the Alzheimer's crowd!

Visual clues. As we fly, we need several cues to tell us what the plane's attitude is. Probably most important is it upright or downside up? We need to be able to see the wing's bank angle clearly, especially on landing approach. And it's nice to know whether the nose is up or down! Putting it all Together. The actual colors used are not nearly as important as CONTRAST. Large areas of contrasting colors, conforming to the plane's shape, will show up best in varying conditions. Have contrast between the top and the bottom and along the wing, including the leading edge area. Some type of contrasting color line or stripe along the side is good, also.

Note: Both the Navy and the Air Force use these principles for their training planes, a situation where visibility and safety are paramount. Both services use white, with large contrasting areas of orange or orange-red. 'Nuff said??

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CRASH ETIQUETTE [from LIRCS Newsletter, Long Island, NY.]

While bent over your model tweaking the needle valve, too often you hear "I ain't got it...," followed by a low frequency thump. Usually, several expletives will be inserted, some used imaginatively. A hand-crafted masterpiece of airframe miniaturization crammed with state of the art electronic equipment and powered by an exquisitely machined engine is no more. The pilot, who is frequently the builder/owner, has made an unscheduled landing or has discovered the radio in his hands has a greater range than the eyes in his head.

Your immediate problem is how to react. Generally, it is considered bad form to immediately ask if you may borrow the pilot's glow plug battery. Similarly, you probably shouldn't ask if he's finished with the clip.

Any equipment related reasons for the crash you hear are by definition reasonable. Pilot error is too rare and sensitive to suggest, so don't say, "That's odd, I haven't had any problems on that frequency today," until at least an hour after the crash. Offer to help go look. Don't say, "It sounded like it hit something solid." Note that most lost models are found and returned. Don't ask if he had his name and phone number in the model or wonder out loud if the model hit a house or car.

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If it looks like more than enough people have "volunteered" to help with the search, try to weasel out of going. There are ticks and poison ivy out there, and seeing a grown man cry isn't pleasant. If the pilot takes a plastic bag with him or comes back empty handed to get one, assume the worst. Actually, in a really bad crash, two hands and a pocket are enough space for everything worth salvaging.

Whatever you do, don't hold a postmortem on the spot. The pilot probably doesn't want to discuss:
battery condition
poor construction
pilot error
used rubber bands
fuel tank capacity
light blue covering
model selection vs. pilot skill

As best you can, avoid specifics, sound supportive, and look appropriately grave. You'll want the same consideration some day.

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FLYING SOMEWHERE ELSE! - by Clay Ramskill

Our flying field is certainly not the worst to be found in the area - its not the best, either. We fly there because we like the field, we like the people, its comfortable to us. But sometime, we're probably going to fly at other fields.

Perhaps the easiest, most painless way to do this is by invitation from a member of another club. Whenever possible to accept such an invitation, do so. You will enjoy the experience of meeting other people, seeing how they do things, seeing their aircraft and so on. And you will get the experience of flying from a different locale; this is not as easy as it seems! The different surroundings, the lack of the usual visual cues you're using (whether you know it or not) and unfamiliar people and aircraft types surrounding you puts a heavy load on your nervous and sensory systems. If you're there by invitation with a friend it really helps.

The worst case scenario is when you've moved to a new city - you may have made a phone call or two, but you basically arrive at some club's field as a total unknown, and essentially end up "showing your stuff" to the watchful eyes of numerous club members who are in the process of evaluating you, as you are them.
NOT a relaxing situation!

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And in between these two extremes are a number of interesting and pleasurable ways to fly from another field. You see the "advertisements", flyers posted at hobby shops, or in Model Aviation, for various events:

Open House- A club just opens their field for others to come watch or fly; you do need to check and see which is the case unless its obvious from their flyer. This is a pretty stressless way to fly from another field and meet some other flyers.

Fly-in- More common than open houses, and usually more structured, these are meant to get other flyers in to fly and socialize, and are also money-makers for the host club. A landing fee is generally charged, there will usually be a frequency impound, aircraft inspection, a rules brief, and so on to ensure safety. There may also be raffles of neat equipment, good food for sale, a vote for best plane in various categories with prizes, perhaps other pilot prize drawings, and maybe some neat flying demos. Generally there is no competitive flying at a fly-in.

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Fun Flys: These can range anywhere from guys doing crazy events with their sport planes just for the fun of it or for a ribbon, all the way to dog-eat-dog competition with specialized aircraft. This is another situation where it would be a good idea to make sure of just what you're getting into! Our idea of a fun fly, and the "sorta" competition we do, may be a long way from some other clubs concept, where its an actual competitive event.

Competitive Events- These are highly structured, usually adhering to AMA rules and guidelines for the events. Promotions will indicate the numbered AMA competitive events to be flown; the AMA rules indicate the type of plane and all the particulars of how the competition is run. These AMA class events cover the whole range of modeling - from racing, to combat, pattern to rubber powered free flight. You should be very familiar to the AMA procedures involved before even thinking about entering such contests. Those who do find them stimulating and fun.

Regardless of the type of function you're going to attend, be sure to look very carefully at the literature advertising it. Many functions have limitations, depending on what the Host club is into and what they're capable of handling. For instance, they may require IMAA legal planes - these are large planes, covered by IMAA rules. Restrictions may be for warbirds only, or for WW2 warbirds only. Or 4-strokes only. Or AMA #301 events only. Or whatever!

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Nearly all the ads will give a POC - a point of contact. It would be wise to give the contact person a call to make sure you know what you are getting into before you drive all the way to East Somewhere. And make sure you have GOOD directions to the field involved. Don't settle for "just follow the signs from downtown"!

A few pointers for going to ANY other field to fly. HAVE your AMA card (not a copy); you probably won't fly without it. Any AMA sanctioned event requires that your radio be "1991 certified". Expect that your plane and perhaps the radio will receive a thorough safety check. Be sure your plane has your name and number nor within, an AMA requirement. Have the appropriate frequency number and red streamer, as well as your name, on your transmitter.

On arrival, get familiar with the frequency control system in use. Be sure that you receive a briefing on any peculiar field rules - it's amazing how often you find out about these AFTER you've unwittingly broken them! Be sure you're aware of field and/or event requirements; sometimes a "spotter" (someone who stands beside you and tells you when you're about to hit another plane!) is required for each flight. Maybe there is no taxiing allowed at the field or for the event. Sometimes you're only allowed to start engines out at the runway; i.e. no running engines in the pits. Some clubs may have a time limit for how long you can fly, or how long you can hold on to a frequency pin.

Be sure to take necessary items with you - the host club may not provide chairs, your favorite beverage, or shelter for you or your plane. You should certainly have a few bucks with you - for landing fees, to enter a raffle, or to buy something neat that's for sale. And if at all possible, take a friend. That way you have someone to talk to, you can trade "spotting" duties, etc., and perhaps ease each other's apprehensions about flying in front of a bunch of strangers!

But by all means, when you see a good opportunity to fly at a different facility, do so. You will be treating yourself to a taste of the wonderful combination of diversity and cohesiveness that make our hobby such an interesting pastime.

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RADIOS -- AM, FM, PCM -- WHICH SHOULD YOU BUY? - by Bob Steele [from Flying Circuits, Inc.]

Buying a new radio? What type do you plan to buy? Do you know what criteria to use in judging radio types or brands? I get a lot of questions on buying radios and I hope to clear some of them up in this article. The first and most important thing to realize is that the quality of the radio you buy can determine how long you keep the airplane you intend to fly it in. Most likely, you have a substantial investment in both time and money in your model and you don't want to see it crash and have your investment wiped out! We're not necessarily talking about price here, but quality.

A great deal of work has gone into receiver (hereafter abbreviated RX) design since the AMA began its frequency utilization plan a few years back and it has paid big dividends! The new Dual Conversion and/or ABC&W RX designs are interference free except when someone turns on a transmitter (abbreviated TX) on your channel. In some cases, metal to metal electrical noise may cause a problem. I would urge you to check the manufacturer's RX specifications to be sure they meet industry standards. Compare one company's specs against another company, so you can be sure what you are buying! If you can't obtain specs for a manufacturer's RX, then don't buy from them!

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Now, on to the transmitter! There are basically three types of TX's available, the basic four channel, the six channel with dual rates and maybe some other bells and whistles, and then there are computer programmable radios. (PCM radios have a computer in them, too, but we'll leave that until later.) Computer programmable radios are used by sailplane flyers, most all serious pattern and helicopter flyers, and a lot of sport flyers who want the versatility and 4 to 8 aircraft memory offered by these computerized marvels. Most beginners start by buying the basic 4 channel setup, and if they stick with the hobby, switch to one of 6 or 7 channel rigs as their skills increase and they demand more from their radio. The gimbals in the TX stick assemblies are the first link in the electronic chain that connects our hands to our aircraft control surfaces. These stick assemblies are critical to good control and should be of the best quality. Buy something that feels good to you and whose servos track the stick movements well!!

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Which brings us logically to the servos! I have stopped using non-ball bearing servos except in those instances where they will be installed in a small (under .35) powered plane or a 2 meter glider. Servo resolution is much better and you do not encounter the problem of the top case output drive hole wearing egg-shaped as they do in an unbushed case. If possible, take the next step and get a coreless motor and it will cost you MORE money and more current drain during the flight, but the better resolution is worth it! Here again, it's a question of protecting your investment by buying quality.

Back to the original question -- AM, FM, or PCM? I still fly a lot of planes on AM and have not had any trouble. I use dual conversion receivers only. There is no reason to give up on this type of equipment if you already own some. If your favorite TX is an AM only TX, just make sure you use good RXs and go on flying AM. Suppose you're buying a whole new outfit? Leaving the compatibility question out of it, I would opt for plain FM not PCM since you will save $40 to $60 that you could better spend on good servos! All you are buying with PCM is failsafe in case you get interference. I have seen one plane saved by failsafe (because it never left the ground) and watched two others go straight in under failsafe so my choice is no PCM. One thing we need to straighten out here! I recently read one article by a supposed expert who stated that PCM radios used 1024 bits of resolution while FM or PPM used only 512 bits of resolution and that made PCM better! FM or PPM doesn't use any bits at all! PPM stands for Pulse Positions Modulations and is infinitely variable. Incidentally, AM radios also used PPM as a modulation scheme. The radios which do use 512 bits are older PCM types which I believe are no longer available. PCM stands for Pulse Code Modulation and seems to have been developed to eliminate certain types of interference back before we had dual conversion receivers. Its reason for use has therefore disappeared. What pulse code modulation does is convert the analog signal from the TX stick into a true binary code by means of a microprocessor chip in the TX. This binary code is then sent to the RX, where by means of another microprocessor chip, it is converted back to an analog signal and forwarded to the servo for which it was intended. It is interesting to note that ALL servos are basically identical, whether they are to be used with AM, FM, or PCM radios. Although you may have to change connectors, you can use any servo with any radio.

So, it's still your money and your choice, but as far as I'm concerned, I'm not wasting my bucks on PCM when I can spend it on better servos, a new engine, or maybe even a new airplane!

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RC and the WEB by Clay Ramskill ( cramskill@arlington.net )

Meet Rich and Mary. They live in the Northwestern U.S., are members of a thriving RC club; he's the Secretary, she does a really nice newsletter. They're both nice folks who write well, have a menagerie of critters around their home (including a small herd of Llamas), and enjoy RC people and flying.

As much as I'd like to, I've never met Rich or Mary. I've never even talked to them. But I've gotten their newsletter, transmitted to me in full color in just a couple of minutes. I've corresponded with them, exchanged some files -- all through my computer.

On the World Wide Web portion of the Internet, modeling, individuals, clubs, and national organizations (like the AMA) have an ever-increasing presence. From Iceland to Australia, modelers share pictures, information, and experience to whoever may seek it out.

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You can order parts for your plane or engine. You can send and receive electronic messages (E-mail) in a flash to any similarly equipped computer. You can get the specifics of Dr. Selig's latest low speed airfoil research, or download (retrieve to your computer) other aerodynamic information. You can read magazines. You can find RC flying sites in any state, or find information on RC clubs. You can find out how to tune your engine. And most of everything you do find is only the tip of a very huge iceberg!

All you need is a computer with a modem (connects your computer to your phone line), access to the internet, and software to make it all work (a browser). The advice of someone who's already "there" is a good idea, too.

The internet is arranged in several formats; the easiest to use and the most rapidly growing portion is the World Wide Web (www). Under this protocol, text, pictures and other data can be sent worldwide, as quickly as calling across town. Hundreds of thousands of individuals, companies and organizations host "home pages", which may only be a small amount of information or be the front for an extensive collection of goodies. And any picture or word can be highlighted as a "link" - if you click on it, you are transported to another site, which could be anywhere in the world! You see the "addresses" for these sites increasingly in your paper, magazines, on the TV, even billboards as folks jump onto the information superhighway.

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The AMA "page" ( http://www.modelaircraft.org/ )is a good starting point -- they give you staff directories, contest schedules, lots of stuff you can download to your computer (like an application to join the AMA), and lots of "links" to other WWW sites all over the world. Tower Hobbies ( http://www.towerhobbies.com/ ) and Hobby Shack have even more extensive sites, including club listings and full catalog and ordering capability -- plus, even more links to other sites.

Many RC clubs also maintain their own WWW pages. Typically, they will include information about their club, perhaps a map to the flying field, several editions of their newsletter, and pictures of their field and members' models. Some clubs even have two newsletter editors -- one for "snail mail" and one to do the WWW edition. Clubs will also include links to other clubs and related organizations, like their local city Chamber of Commerce.

Individuals also sometimes host RC related WWW pages. These range in complexity from a few pictures of a guy and his RC model, to extensive compilations of information, pictures, or trivia. And, as always, more links to other sites!

"Online Services" such as CompuServe, Prodigy, and America Online also have areas for modelers. In CompuServe, it is called ModelNet, and it includes archive pictures, data, and "chat groups" where folks can trade BS with each other. (Some of these guys need to get a life!) Usenet, another area of the Internet, is also a "trade stories" type of operation.

I've "visited" RC sites all over the world, not to mention the U.S. The logos shown are from Norway, Cyprus, Australia, and Belgium -- only a few of the myriad of clubs and organizations with a WWW presence.

If you have the time to poke ("surf") around on the WWW, I highly recommend it. Just don't let it detract from your building and flying time!

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THE BIG LIE - by Ron Lockhart -by Ron Lockhart - from "the Radiator"; Atlantic City Skyblazers, Atlantic City, NJ

OK, so that's a bit harsh. I'll be charitable and call it a Big Fib. You have heard it, or read it, probably many times over. Seems like we often hear, "It flew beautifully, didn't even need any trim!". Magazine articles on kit reviews or new designs like to use the big fib. Too often we read: "It practically flew right off the drawing board." or, "The maiden flight was a dream, it didn't even need the transmitter trims changed." A minor variation is the "All it took was two clicks of left rudder and it flew great." or, "It trimmed perfectly on the transmitter".

Don't you believe it! It is a rare event that a new airplane flies well without trim changes. It may be a proven design, properly constructed, balanced and set up according to the instructions... But, the designer can't know everything about the way it was built and the way it will be flown. It can, and SHOULD BE, trimmed, adjusted, and changed to make it fly more the way YOU want it too. The recommendations in the instructions are a good place to start, and make it highly likely that your new craft will survive its test flight. So after that first flight, now what?

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TRANSMITTER TRIMS- If some of them are not close to centered, adjust that control surface so they will be closer to center. Make small adjustments at a time, one to three turns on the clevis. Adjust all control surfaces, and the nose wheel. If all the trim lever travel has been used, it will probably take three turns to get it close to center.

CONTROL SURFACE THROW- Reduce control throws on the rudder and ailerons if they are too sensitive. Make the reductions a little bit, move one hole on control horns or about three turns on the threaded stud type control horns often used on ailerons. If some controls were not very effective, or not sensitive enough, increase the throw a little. If the elevator is too sensitive, there are two possibilities- 1) Reduce elevator throw, or 2) Move the balance point, CG or Center of Gravity, forward. If the plane flew smoothly, but was sensitive to small amounts of elevator stick, then reduce the elevator throw a little. If the plane was smooth and landed going fast with most of the up elevator being used, increase the throw a little. If the plane tended to climb, would not settle into stable flight, tended to balloon on landing, or needs down elevator trim, then you likely have a tail heavy plane and need to move the CG forward. See the next paragraph.

CG/CENTER OF GRAVITY/BALANCE POINT- Tail heavy airplanes are tough to fly even for an experienced pilot. They have lots of bad habits- a tendency to lift off at too low an airspeed, balloon on landing, resist being trimmed for level flight, and so on. Move the CG forward to reduce those things. Add nose weight, or shift the battery or other equipment forward in the fuselage. If it means adding weight to your plane, do it. This is one case where the added weight is well worth it.

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TOO MUCH, TOO SOON - by Clay Ramskill

He'd done this several times before -- it was a real crowd-pleaser. Take off and immediately pull nearly vertical, climbing out almost straight up. Aligning the 60-size "stick" with the runway, he gunned the powerful .90 4-stroke, then yanked the stick back. With a roar, the Ugly Stick pointed its nose up, but only mushed forward, barely climbing. Completely stalled. The nose began a sickening dive to the left. "I ain't got it!" he shouted as the plane crashed.

Radio problem? CG problem?

No. All too often we see the above scenario -- after the trainer, a relatively "hot" airplane, with lots of power. And often as not, the appropriate warning sign is there -- the trainer was crashed, not worn out or sold. Then the relatively inexperienced pilot gets a "hot" plane, or an appropriate intermediate plane, but overpowered.

Perhaps there should be an intermediate training program, too. So that a pilot knows he must be able to use appropriate rudder with a strong engine. So he knows that the stall characteristics of an Extra are not the same as on his trusty Eagle 3. So that he knows how to recover from a deep stalled attitude. So that he knows not to get into that deep stall 10' above the runway.

It's bad enough that some individuals end up crashing some awfully nice hardware before they even get the chance to appreciate it properly. There is a safety factor involved also. The fewer crashes, the less likely a crash will occur in the pits, on a car, or someone's head.

Newer pilots need a bit of coaching -- sometimes they need the brutal hard facts: "Son, that plane's too much for you right now." They need some patience -- to take some time to really learn flying on a trainer or intermediate plane before moving up to "heavy iron."

More experienced flyers need to be more involved with the less experienced -- help them get the skills they need before they get into trouble.

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FOR SMOOTHER FLYING -- TRIMMIT! by Clay Ramskill

Any full scale pilot will tell you that the secret to smooth precision flying is to have the plane trimmed up, always. This is especially important to formation work, instrument flying, bombing runs, and so on.

Keeping our RC aircraft in trim is also important to our flying, although there are some important differences.

But, first, what do we mean by "trimmed up"? We generally trim for straight and level flight conditions -- such that if we take our thumbs off the sticks, the plane will continue flying straight and level, within the scope of the stability of the plane. A couple of facts to ponder: 1) A plane can only be trimmed for ONE flying speed; 2) The more stable the plane, the more trim change occurs when the speed is altered. Note that we're speaking of mostly PITCH (elevator) trim here -- lateral and directional (aileron and rudder) trim will generally not change as speed increases -- if they do, you've got other problems, such as warped wings, crooked tailfin, or thrust line problems.

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In a full size airplane, the trims are located where it's easy to do the trimming, without having to go "hands off" the stick or wheel. Unfortunately, the RC transmitter is not so convenient, and it's just not very easy to constantly be messing with the trim. So most pilots trim for the fastest condition they normally fly, usually full throttle, and full speed. That means that in any slower condition, some back stick is required for level flight. For most of us, this is best -- because pushing on the stick seems to give less precise control than pulling on it. And if your normal flight involves flying around at 1/2 throttle, then by all means trim for that condition, keeping in mind that the addition of more throttle (and speed) will result in a nose up climb.

Now, a bit about rudder and aileron trim. Assuming that you don't have warped wings, a crooked tailfin, or bad thrust alignment problems, the aileron trim should, once you get it set, remain set. That's because the linkage is short, and even if the links shrink or expand, they will both raise or lower the ailerons the same amount. But the rudder link, unless you have a pull-pull system, will deflect the rudder with shrinkage or expansion of the pushrod. And that pushrod is usually pretty long, meaning significant expansion in the heat of the day. If your rudder is offset to one side, your plane will fly oddly, because it will be in a continuous slip, or skid, and may also want to roll to one side.

The point here is that you are wise to check the rudder trim (by looking at the rudder) frequently, if not every flight. And if you get airborne and the plane flies weird and wants to roll, it's more likely to be rudder trim than aileron trim that is at fault. This is especially true of trainer type planes because of the high wing dihedral, and is most true of planes using "nyrod" type pushrods -- because the nyrods have a rather large expansion rate compared to other type pushrods.

Those of us who have flight instructed in full size planes can quickly recognize the symptoms of out of trim flying -- the plane constantly veering off course in the same fashion (left, right, up, or down) then being abruptly corrected, then veering off again -- the cycle being constantly repeated. In such a situation, the pilot is more fighting the plane than just flying it! And flying an out of trim plane is not an enjoyable experience!

If you relate to all this, seek out a more experienced flyer to help you get the beast in trim, and to show you ways to check it for yourself. You might be amazed at how much easier flying your plane can be! ... Clay

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TWO IS BETTER THAN ONE (Does that count for servos?) - by Ron Lockhart - (Does that count for servos?) - by Ron Lockhart - via internet- published in "The Radiator", Atlantic City Skyblazers, Atlantic City, N.J.

Take the case of the lonely aileron servo. Normally one servo is mounted in the center of a wing to drive two ailerons. To get the servo output wheel motion to each aileron, we often use a set of aileron torque rods. Sometimes linkage from the servo goes to a bellcrank for each aileron, and then to the aileron. Yet another method is to run nyrod casings from the servo into the wing and bend them 90 degrees to get them to the ailerons. All of these linkage methods have their problems. The main one is the slop or play that can be felt at the aileron.

Bad stuff - slop/play/looseness in ailerons (or any control surface). It contributes to possible control surface flutter, linkage and servo wear, and maybe servo failure. It makes the airplane harder to fly well, because the airplane wanders in heading and altitude. Each linkage point, the torque rod bearing, the bellcrank pivot, each pushrod that flexes, etc, add to the un- desirable play at the aileron. Curved nyrod casings add drag and make it hard for the servo to find neutral.

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How about using two aileron servos, one for each aileron.? Mount them partly outboard in the wing ahead of the ailerons. Both servos can be plugged into the receiver aileron channel using a "Y" cord. It's that simple. If your radio has a provision for a left and right aileron channel, use it. That has benefits that could be the subject of another article. The super simple linkage is the beauty of this system. One short push rod goes from the servo wheel to the aileron horn in a straight line.

Minimal / no slop! Great! The two servo system is not perfect either though. You have to find another servo, (yes, same kind!) and build servo mounts into the wing. That isn't tougher than torque rods, bellcranks, and such, just different. Depending on how far out on the wing the servos are mounted, you may need to lengthen the servo cords (using an aileron extension is the easy way) to reach the receiver. Extra weight? -Two servos may not be much heavier than one with the extra linkage. Since each servo is doing half the work (actually less than half since linkage drag is reduced) you could use smaller servos to save weight.

Will two aileron servos be better than one for your model? As all things it seems, it depends. The bigger and faster a model is, and the more precisely you want the aircraft to fly, the more benefit you will find in using two servos. There is also some benefit in having the redundancy of two servos in case of a servo or linkage failure. In some installations, not having the one center mounted aileron servo protrude into the fuselage area is helpful.

Two is better than one, probably more often than we think!

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